The forbidden fruit

The forbidden fruit was not sexual relations

Eve wanted to be like God, deciding for herself what is good and bad
A Grasp at Moral Independence
The tree of knowledge was a literal tree. However, it represented God’s right as Ruler to decide what is good and bad for his human creation. To eat from the tree, therefore, was not just an act of theft—taking that which belonged to God—but also a presumptuous grasp at moral independence, or self-determination. Note that after lyingly telling Eve that if she and her husband ate the fruit, they ‘positively would not die,’ Satan asserted: “For God knows that in the very day of your eating from it your eyes are bound to be opened and you are bound to be like God, knowing good and bad.”—Genesis 3:4, 5.
When they ate the fruit, however, Adam and Eve did not receive godlike enlightenment on good and bad. In fact, Eve said to God: “The serpent—it deceived me.” (Genesis 3:13) Still, she knew of God’s command, even restating it to the serpent, Satan’s mouthpiece. (Revelation 12:9) Hence, her act was one of willful disobedience. (Genesis 3:1-3) Adam, though, was not deceived. (1 Timothy 2:14) Instead of loyally obeying his Creator, he listened to his wife and followed her independent course.—Genesis 3:6, 17.
The forbidden fruit was not sexual relations
By asserting their independence, Adam and Eve irreparably damaged their relationship with Jehovah and inflicted sin’s imprint upon their organism, right to its genetic foundations. True, they lived for hundreds of years, but they began to die “in the day” of their sin, as a branch severed from a tree would. (Genesis 5:5) Moreover, for the first time, they sensed an internal disharmony. They felt naked and tried to hide from God. (Genesis 3:7, 8) They also felt guilt, insecurity, and shame. Their sin produced an upheaval within them, their consciences accusing them of wrongdoing.
To be true to himself and to his holy standards, God justly sentenced Adam and Eve to death and expelled them from the garden of Eden. (Genesis 3:19, 23, 24) Thus, Paradise, happiness, and everlasting life were lost, while sin, suffering, and death resulted. What a tragic development for the human race! However, immediately after sentencing the couple, God promised to undo all the harm resulting from their sin without compromising his own righteous standards.
Jehovah purposed to make it possible for the offspring of Adam and Eve to be freed from sin’s deadly grip. He accomplished this through Jesus Christ. (Genesis 3:15; Matthew 20:28; Galatians 3:16) Through him, God will eliminate sin and all its effects and will make the earth into a global paradise, just as he purposed in the beginning.—Luke 23:43; John 3:16.